A high-ranking Al-Qaeda linked militant from the group believed to be behind a series of high-profile attacks against U.S. forces in Afghanistan was gunned down overnight on the outskirts of Islamabad, Pakistan's capital city.

Nasiruddin Haqqani, a senior figure in the feared Haqqani network, was standing at a bakery to buy bread when two gunmen on motorcycles approached and opened fire, according to an eyewitness who asked to not be identified due to fear of reprisals.

Haqqani's associates hurried him into his black SUV and sped him away. The attack left bullet holes in the bakery's wall, and Haqqani's blood splattered over the floor.

It happened in Bara Kahu, a small village a few miles away from Islamabad. No group has claimed responsibility for the attack.

The Haqqani network is among the most feared and powerful militant groups operating along Pakistan's border with Afghanistan. Senior State Department officials have repeatedly blamed the group for some of the deadliest attacks against U.S. Forces in Afghanistan, including major assaults on American bases that have killed or injured dozens of American soldiers.

Unlike other high-ranking members of the militant group, Nasiruddin is believed to have kept a low profile. His primary role was a financier, and there is no indication he was involved in planning or day-to-day strategic operations.

The Haqqani network is led by Nasiruddin's brother, Sirajuddin Haqqani. Their father, Jalaluddin Haqqani, founded the group and is well-known for fighting the Soviets after they invaded Afghanistan in 1979.

Senior State Department officials have criticized Pakistan for not doing enough to target the Haqqani network, which is aligned with Mullah Omar and the Taliban. It's unclear how long Haqqani had been living so close to the Pakistani capital, or how he managed to live so openly without being caught. Residents would often see Haqqani's black SUV in the area, but weren't aware who it belonged to.

His death comes after a U.S. drone strike killed another militant leader, Hakimullah Mehsud, in North Waziristan, a largely lawless area that straddles the border. Mehsud, the leader of the Pakistani Taliban, was killed just after meeting a delegation of fellow Taliban commanders to discuss a peace deal with the Pakistani government.